Electric discharge tube



8. 1956 H. J. M. VAN TOL ELECTRON DISCHARGE TUBE Filed June 12, 1952 INVENTOR Hendrikus Johannes Marie Vcm Tol lands, assignor to Hartford National Bank and Trust Company, Hartford, Coma, as trustee Application June 12, 1952, Serial No. 2%,069 Claims priority, application Netherlands lune 22, 1951 3 Claims. (Cl. 313-331) This invention relates to electric discharge tubes the cathode of which is provided with a collar and a striplike leading-in conductor which is soldered to the cathode at the very end adjacent the collar.

Such discharge tubes have a limitation in that the cathode can be held in a downward direction but not in an upward direction, with the result that the cathode may move upwards and the lower end may even become detached from the centering member, in that the cathodeconnecting wire cannot extend straight downwards since the leading-in conductors, which constitute the contact pins, are arranged to follow a circle, so that the thin leading-in conductor must extend almost horizontally and is thus prevented from obstructing upward movement of the cathode without the use of additional expedients.

Instead of using a collar it is known to use a connecting conductor which on the side of the centering member adjacent the electrode system is bent over and at the other side of the centering member is bent out of engagement with the cathode. However, such a construction has considerable disadvantages. Due to the fact that the bentover part is arranged Within the electrode system and is located immediately above the recess formed in the mica for this conductor and must have a comparatively large cross-sectional area to be able to absorb the force by means of which the cathode is pressed into the centering disc during the component mounting, the more so as the upper end of the bent-over part cannot be soldered in position but is free, this bent-over part must extend to a comparatively large distance outside the cathode surface with the result that either the cathode'grid spacing must be large or the grid must end at a short distance from the centering member, which, however, is inconvenient. However, such a thick conductor brings about intense heat dissipation, apart from the fact that it is not simple to bend and arrange the conductor in the correct manner, since the weld finds its way into the aperture formed in the centering member.

When using a collar, which may be circular, the height of this collar may be low since the collar is not bound to lie in face of a recess as mentioned above. In spite of its low height such a collar is consequently adapted to absorb far greater forces than in a member as above described. In addition the provision of such a collar is effected by machine and does not involve any complication in practicev It is possible to unite the advantages of the two methods and largely to obviate the said disadvantages. For this purpose, in an electric discharge tube comprising a cathode of the indirectly heated type, the cathode sleeve of which is provided at one end with a collar and is arranged in an insulating centering member at least by means of this end, a thin supply conductor being secured to the extremity of this end of the cathode sleeve, this supply conductor is formed between the weld and the centering member in a manner such that this conductor jointly with the collar holds the cathode in the aperture of the insulating member against movements in the direction of length of the cathode. For this purpose the supply conductor may be bent in the form of a loop or severed immediately below the centering member. In the latter case, the free end of the conductor springs slightly away from the cathode sleeve and thus locks the cathode.

rates atent O In order that the invention may be readily carried into effect, two examples will now be described in detail with reference to the accompanying drawings, in which:

Fig. 1 shows a cathode prior to component mounting;

Fig. 2 shows a cathode subsequent to component mounting and Fig. 3 shows an alternative embodiment of the inven' tion.

Referring to Fig. l, the cathode sleeve 1 comprises at one end a collar 2. At the very end 4 the strip 5 is soldered in position in a manner such that the part 3 extends beyond the weld. Subsequently to the cathode sleeve being mounted in a centering disc 6 (Fig. 2) the part 3 is bent out just below the centering disc 6 to form a loop 7, for example with the use of tweezers,- so as to fix the cathode also in an upward direction. The thickness of strip 5 is low so that little heat dissipation ensues and even the recess in the aperture in the centering disc can frequently be dispensed with thus assisting in simplifying the mounting operation. ]f a recess is provided it may be small enough to prevent difiiculty in view of the other apertures in the centering member.- The loop is comparatively strong since it is secured in position at both ends.

In the embodiment shown in Fig. 3 the part 13 of conductor 10 is severed immediately below the centering. disc 11 and the excess part which is gripped between the cathode sleeve 8, the collar 9 and the centering disc 11 is removed. The part 13 slightly recoils or is bent back so that its end engages the centering disc and thus holds the cathode in an upward direction.

What I claim is:

1. In an electric discharge tube the combination comprising a s1eeve-type, indirectly heated cathode, said sleeve being provided with a collar adjacent to one end thereof, an insulating centering member positioned in said tube and having an aperture therein, part of said cathode being positioned in said aperture, and a relatively thin cathode supply conductor secured intermediate its ends to said cathode at a place at one end thereofv adjacent to the bottom circumferential edge of said cathode, said supply conductor having a free end held in said aperture between said collar and said centering member whereby said supply conductor and said collar coact to prevent said cathode from moving in axial directions thereof.

2. In an electric discharge tube the combination as set forth in claim 1 wherein said supply conductor is bent into the form of a loop and the free end thereof is gripped between said cathode and said centering member.

3. In an electric discharge tube the combination comprising a sleeve-type, indirectly heated cathode, said cathode being provided with a collar adjacent to one end thereof, an insulating centering member positioned in said tube and having an aperture therein, part of said cathode being positioned in said aperture, a relativeE thin cathode supply conductor being secured intermediate its end to said sleeve at a place at one end thereof adjacent to the bottom circumferential edge of said cathode, and one end of said supply conductor engaging the underside of said centering member, the portion of said supply conductor between said centering member and the point of securement of said supply conductor to said sleeve being at an acute angle to said centering member.

References Cited in the file of this patent UNITED STATES PATENTS 1,974,916 Goodwin Sept. 25, 1934 1,991,174 Rose, Jr. Feb. 12, 1935 2,206,504 Kmyon July 2, 1940 2,266,622 Green Dec. 16, 1941 2,578,370 Peck Dec. 11, 1951 

